diff --git a/modules/openapi-generator/src/main/resources/scala-sttp/api.mustache b/modules/openapi-generator/src/main/resources/scala-sttp/api.mustache
index 29ef3ce991bb..cb72041f6a4f 100644
--- a/modules/openapi-generator/src/main/resources/scala-sttp/api.mustache
+++ b/modules/openapi-generator/src/main/resources/scala-sttp/api.mustache
@@ -10,8 +10,7 @@ import sttp.model.Method
 
 {{#operations}}
 object {{classname}} {
-
-def apply(baseUrl: String = "{{{basePath}}}") = new {{classname}}(baseUrl)
+  def apply(baseUrl: String = "{{{basePath}}}") = new {{classname}}(baseUrl)
 }
 
 class {{classname}}(baseUrl: String) {
@@ -20,7 +19,7 @@ class {{classname}}(baseUrl: String) {
 {{#javadocRenderer}}
 {{>javadoc}}
 {{/javadocRenderer}}
-  def {{operationId}}({{>methodParameters}}): Request[{{#defaultReturnType}}Either[Either[String, String], Unit]{{/defaultReturnType}}{{^defaultReturnType}}{{#separateErrorChannel}}Either[ResponseException[String, Exception], {{>operationReturnType}}]{{/separateErrorChannel}}{{^separateErrorChannel}}{{>operationReturnType}}{{/separateErrorChannel}}{{/defaultReturnType}}, Any] =
+  def {{operationId}}({{>methodParameters}}): Request[{{#separateErrorChannel}}Either[ResponseException[String, Exception], {{>operationReturnType}}]{{/separateErrorChannel}}{{^separateErrorChannel}}{{>operationReturnType}}{{/separateErrorChannel}}, Any] =
     basicRequest
       .method(Method.{{httpMethod.toUpperCase}}, uri"$baseUrl{{{path}}}{{#queryParams.0}}?{{#queryParams}}{{baseName}}=${ {{{paramName}}} }{{^-last}}&{{/-last}}{{/queryParams}}{{/queryParams.0}}{{#isApiKey}}{{#isKeyInQuery}}{{^queryParams.0}}?{{/queryParams.0}}{{#queryParams.0}}&{{/queryParams.0}}{{keyParamName}}=${apiKey.value}&{{/isKeyInQuery}}{{/isApiKey}}")
       .contentType({{#consumes.0}}"{{{mediaType}}}"{{/consumes.0}}{{^consumes}}"application/json"{{/consumes}}){{#headerParams}}
@@ -36,7 +35,7 @@ class {{classname}}(baseUrl: String) {
         {{>paramMultipartCreation}}{{^-last}}, {{/-last}}{{/formParams}}
       ).flatten){{/isMultipart}}{{/formParams.0}}{{#bodyParam}}
       .body({{paramName}}){{/bodyParam}}
-      .response({{#defaultReturnType}}asEither(asString, ignore){{/defaultReturnType}}{{^defaultReturnType}}{{#separateErrorChannel}}asJson{{/separateErrorChannel}}{{^separateErrorChannel}}asJsonAlwaysUnsafe{{/separateErrorChannel}}[{{>operationReturnType}}]{{/defaultReturnType}})
+      .response({{#separateErrorChannel}}{{^returnType}}asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))){{/returnType}}{{#returnType}}asJson[{{>operationReturnType}}]{{/returnType}}{{/separateErrorChannel}}{{^separateErrorChannel}}{{^returnType}}asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))).getRight{{/returnType}}{{#returnType}}asJson[{{>operationReturnType}}].getRight{{/returnType}}{{/separateErrorChannel}})
 
 {{/operation}}
 }
diff --git a/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/FakeApi.scala b/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/FakeApi.scala
index a7006555fe4e..84ce29a85bcb 100644
--- a/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/FakeApi.scala
+++ b/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/FakeApi.scala
@@ -16,8 +16,7 @@ import sttp.client3._
 import sttp.model.Method
 
 object FakeApi {
-
-def apply(baseUrl: String = "http://petstore.swagger.io/v2") = new FakeApi(baseUrl)
+  def apply(baseUrl: String = "http://petstore.swagger.io/v2") = new FakeApi(baseUrl)
 }
 
 class FakeApi(baseUrl: String) {
@@ -38,6 +37,6 @@ class FakeApi(baseUrl: String) {
       .contentType("application/json")
       .header("_type", underscoreType.toString)
       .header("type_", typeWithUnderscore.toString)
-      .response(asJson[Unit])
+      .response(asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))))
 
 }
diff --git a/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/PetApi.scala b/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/PetApi.scala
index e4897aa24163..a412877580d4 100644
--- a/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/PetApi.scala
+++ b/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/PetApi.scala
@@ -19,8 +19,7 @@ import sttp.client3._
 import sttp.model.Method
 
 object PetApi {
-
-def apply(baseUrl: String = "http://petstore.swagger.io/v2") = new PetApi(baseUrl)
+  def apply(baseUrl: String = "http://petstore.swagger.io/v2") = new PetApi(baseUrl)
 }
 
 class PetApi(baseUrl: String) {
@@ -57,7 +56,7 @@ class PetApi(baseUrl: String) {
       .method(Method.DELETE, uri"$baseUrl/pet/${petId}")
       .contentType("application/json")
       .header("api_key", apiKey.toString)
-      .response(asJson[Unit])
+      .response(asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))))
 
   /**
    * Multiple status values can be provided with comma separated strings
@@ -150,7 +149,7 @@ class PetApi(baseUrl: String) {
         "name" -> name,
         "status" -> status
       ))
-      .response(asJson[Unit])
+      .response(asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))))
 
   /**
    * 
diff --git a/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/StoreApi.scala b/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/StoreApi.scala
index 10699532398f..1cecc3117fe0 100644
--- a/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/StoreApi.scala
+++ b/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/StoreApi.scala
@@ -17,8 +17,7 @@ import sttp.client3._
 import sttp.model.Method
 
 object StoreApi {
-
-def apply(baseUrl: String = "http://petstore.swagger.io/v2") = new StoreApi(baseUrl)
+  def apply(baseUrl: String = "http://petstore.swagger.io/v2") = new StoreApi(baseUrl)
 }
 
 class StoreApi(baseUrl: String) {
@@ -37,7 +36,7 @@ class StoreApi(baseUrl: String) {
     basicRequest
       .method(Method.DELETE, uri"$baseUrl/store/order/${orderId}")
       .contentType("application/json")
-      .response(asJson[Unit])
+      .response(asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))))
 
   /**
    * Returns a map of status codes to quantities
diff --git a/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/UserApi.scala b/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/UserApi.scala
index 6f035512fc27..d8eb054688cb 100644
--- a/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/UserApi.scala
+++ b/samples/client/petstore/scala-sttp/src/main/scala/org/openapitools/client/api/UserApi.scala
@@ -18,8 +18,7 @@ import sttp.client3._
 import sttp.model.Method
 
 object UserApi {
-
-def apply(baseUrl: String = "http://petstore.swagger.io/v2") = new UserApi(baseUrl)
+  def apply(baseUrl: String = "http://petstore.swagger.io/v2") = new UserApi(baseUrl)
 }
 
 class UserApi(baseUrl: String) {
@@ -36,13 +35,13 @@ class UserApi(baseUrl: String) {
    * @param user Created user object
    */
   def createUser(apiKey: String)(user: User
-): Request[Either[Either[String, String], Unit], Any] =
+): Request[Either[ResponseException[String, Exception], Unit], Any] =
     basicRequest
       .method(Method.POST, uri"$baseUrl/user")
       .contentType("application/json")
       .header("api_key", apiKey)
       .body(user)
-      .response(asEither(asString, ignore))
+      .response(asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))))
 
   /**
    * 
@@ -56,13 +55,13 @@ class UserApi(baseUrl: String) {
    * @param user List of user object
    */
   def createUsersWithArrayInput(apiKey: String)(user: Seq[User]
-): Request[Either[Either[String, String], Unit], Any] =
+): Request[Either[ResponseException[String, Exception], Unit], Any] =
     basicRequest
       .method(Method.POST, uri"$baseUrl/user/createWithArray")
       .contentType("application/json")
       .header("api_key", apiKey)
       .body(user)
-      .response(asEither(asString, ignore))
+      .response(asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))))
 
   /**
    * 
@@ -76,13 +75,13 @@ class UserApi(baseUrl: String) {
    * @param user List of user object
    */
   def createUsersWithListInput(apiKey: String)(user: Seq[User]
-): Request[Either[Either[String, String], Unit], Any] =
+): Request[Either[ResponseException[String, Exception], Unit], Any] =
     basicRequest
       .method(Method.POST, uri"$baseUrl/user/createWithList")
       .contentType("application/json")
       .header("api_key", apiKey)
       .body(user)
-      .response(asEither(asString, ignore))
+      .response(asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))))
 
   /**
    * This can only be done by the logged in user.
@@ -102,7 +101,7 @@ class UserApi(baseUrl: String) {
       .method(Method.DELETE, uri"$baseUrl/user/${username}")
       .contentType("application/json")
       .header("api_key", apiKey)
-      .response(asJson[Unit])
+      .response(asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))))
 
   /**
    * 
@@ -152,12 +151,12 @@ class UserApi(baseUrl: String) {
    *   api_key (apiKey)
    */
   def logoutUser(apiKey: String)(
-): Request[Either[Either[String, String], Unit], Any] =
+): Request[Either[ResponseException[String, Exception], Unit], Any] =
     basicRequest
       .method(Method.GET, uri"$baseUrl/user/logout")
       .contentType("application/json")
       .header("api_key", apiKey)
-      .response(asEither(asString, ignore))
+      .response(asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))))
 
   /**
    * This can only be done by the logged in user.
@@ -179,6 +178,6 @@ class UserApi(baseUrl: String) {
       .contentType("application/json")
       .header("api_key", apiKey)
       .body(user)
-      .response(asJson[Unit])
+      .response(asString.mapWithMetadata(ResponseAs.deserializeRightWithError(_ => Right(()))))
 
 }